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  • 101.
    Coenen, Pieter
    et al.
    Faculty of Human Movement Sciences, VU University Amsterdam.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Kingma, Idsart
    Faculty of Human Movement Sciences, VU University Amsterdam.
    Boot, Cécile
    EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam.
    Bongers, Paulien
    TNO Healthy Living, Hoofddorp.
    van Dieën, Jaap
    Faculty of Human Movement Sciences, VU University Amsterdam.
    The effect of the presence and characteristics of an outlying group on exposure-outcome associations2015In: Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140, E-ISSN 1795-990X, Vol. 41, no 1, p. 65-74Article in journal (Refereed)
    Abstract [en]

    Objectives: Physical exposures (e.g., lifting or bending) are believed to be risk factors for low-back pain (LBP), but the literature is inconsistent. Exposure and LBP prevalence differ considerably between occupations, and so exposure-outcome associations could be severely modified by the presence of particular occupational groups. We aimed at investigating the influence of such outlying groups on the properties of associations between exposure and LBP.

    Methods: Lifting and trunk flexion were observed for 371 of 1131 workers within 19 groups. LBP was obtained from all workers during three follow-up years. Both exposure variables were associated with LBP (p<0.01) in this parent dataset.

    By removing the 19 groups one-by-one and performing logistic regressions analysis on the 18 remaining groups, we demonstrated that one group, mainly road workers, with outlying exposures and LBP prevalence substantially affected the exposure-outcome association in the total population. In order to further examine this phenomenon, we assessed, by simulation, the influence of realistic sizes (n=4, 8, 16, 32, 64, 128), mean exposures (e=2000, 3000, 4000 lifts and e=30, 40, 50% trunk flexion time) and LBP prevalences (p=70, 80, 90, 100%) of the outlying group on the strength and certainty of the eventual relationship between exposure and LBP. For each combination of n, e and p, 3000 virtual studies were constructed, including the simulated group together with the other 18 original groups from the parent data-set. Average OR, OR confidence limits, and power (p<0.05) were calculated across these 3,000 studies as measures of the properties of each virtual study design.

    Results: ORs were attenuated more towards 1 and power decreased with smaller values of n, e and p in the outlying group. Changes in group size and prevalence had a larger influence on OR and power than changes in mean exposure.

    Conclusions: The size and characteristics of a single group with high exposure and outcome prevalence can strongly influence both the OR point estimate and the likelihood of obtaining significant exposure-outcome associations in studies of large populations. These findings can guide interpretations of prior epidemiological studies and support informed design of future studies.

  • 102.
    Coenen, Pieter
    et al.
    Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    van der Beek, Allard
    Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
    Hallman, David
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Correction of bias in self-reported sitting time among office workers – a study based on compositional data analysis2019In: Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140, E-ISSN 1795-990XArticle in journal (Refereed)
    Abstract [en]

    Objective: Emerging evidence suggests that excessive sitting has negative health effects. However, this evidence largely relies on research using self-reported sitting time, which is known to be biased. To correct this bias, we aimed at developing a calibration model estimating "true" sitting from self-reported sitting.

    Methods: Occupational sitting time was estimated by self-reports (the International Physical Activity Questionnaire) and objective measurements (thigh-worn accelerometer) among 99 Swedish office workers at a governmental agency, at baseline and 3 and 12 months afterwards. Following compositional data analysis procedures, both sitting estimates were transformed into isometric log-ratios (ILR). This effectively addresses that times spent in various activities are inherently dependent and can be presented as values of only 0−100%. Linear regression was used to develop a simple calibration model estimating objectively measured "true" sitting ILR (dependent variable) from self-reported sitting ILR (independent variable). Additional self-reported variables were then added to construct a full calibration model. Performance of the models was assessed by root-mean-square (RMS) differences between estimated and objectively measured values. Models developed on baseline data were validated using the follow-up datasets.

    Results: Uncalibrated self-reported sitting ILR showed an RMS error of 0.767. Simple and full calibration models (incorporating body mass index, office type, and gender) reduced this error to 0.422 (55%) and 0.398 (52%), respectively. In the validations, model performance decreased to 57%/62% (simple models) and 57%/62% (full models) for the two follow-up data sets, respectively.

    Conclusions: Calibration adjusting for errors in self-reported sitting led to substantially more correct estimates of "true" sitting than uncalibrated self-reports. Validation indicated that model performance would change somewhat in new datasets and that full models perform no better than simple models, but calibration remained effective.

  • 103.
    Coenen, Pieter
    et al.
    Vrije Universiteit Amsterdam, Department of Public and Occupational Health, Amsterdam Public Health Research Institute, Amsterdam, The Netherlands.
    van der Beek, Allard J.
    Vrije Universiteit Amsterdam, Department of Public and Occupational Health, Amsterdam Public Health Research Institute, Amsterdam, The Netherlands.
    Jackson, Jennie
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational Health Science and Psychology, Occupational Health Science. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Centre for Musculoskeletal Research. University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational Health Science and Psychology, Occupational Health Science.
    Calibration of self-reported physical behaviours among office workers: A compositional data analysis2019In: ICAMPAM 2019: Oral Abstracts, Maastricht: ICAMPAM , 2019, article id O.11.2Conference paper (Refereed)
    Abstract [en]

    The aim of this study was to develop and evaluate calibration models to predict objectively measured time spent sitting, standing and walking during office work from self-reported time-use compositions using a compositional data analysis (CoDA) approach. Ninety-nine office workers (49 women) at the Swedish Transport Administration participated in an intervention study on relocation to activity-based offices. At baseline and at a 3-months follow-up, physical behaviours (sitting, standing and walking) at work were assessed for five days using a thigh-mounted accelerometer (Actigraph) and by self-report (IPAQ). The time-use composition of the three behaviours was expressed in terms of isometric log-ratios (ILR). Calibration models predicting accelerometry-based time-use from self-reported compositions were constructed using linear regression on baseline data, and then validated using follow-up data. The accelerometer data showed that, on average, workers spent 69.9% of their day sitting, 23.7% standing, and 6.4% walking. The corresponding percentages for self-reports were 71.7%, 21.6%, and 7.4%, respectively. Non-calibrated self-reports were biased: the RMS errors obtained from the ILRs expressing sitting, standing and walking were 0.73, 1.09 and 1.05, respectively. Calibration models reduced these errors by 45% (sitting), 56% (standing), and 76% (walking). Validation of the calibration models using follow-up data from the same workers showed calibration remained equally effective; RMS errors were reduced by 55% (sitting), 58% (standing), and 75% (walking). In conclusion, calibration models for compositional time-use data were effective in reducing bias in self-reported physical behaviours at work, and the models remained effective when used on new data from the same workers. Calibrated self-reports may represent a cost-effective method for obtaining physical behaviour data with a satisfying accuracy in large-scale cohort and intervention studies.

  • 104.
    Commissaris, Dianne A. C. M.
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Departments of Sustainable Productivity & Employability; Work, Health & Care; and Expertise Centre Lifestyle, TNO, Leiden, The Netherlands.
    Huysmans, Maaike A.
    Department of Public and Occupational Health and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands; Body@Work Research Center Physical Activity, Work & Health TNO-VU/VUmc, Amsterdam, The Netherlands.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Srinivasan, Divya
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Koppes, Lando L.J.
    Department of Sustainable Productivity and Employability; Work, Health and Care; and Expertise Centre Life Style, TNO, Leiden, The Netherlands; NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands..
    Hendriksen, Ingrid J.M.
    Department of Sustainable Productivity and Employability; Work, Health and Care; and Expertise Centre Life Style, TNO, Leiden, The Netherlands; Body@Work Research Center Physical Activity, Work & Health TNO-VU/VUmc, Amsterdam, The Netherlands..
    Interventions to reduce sedentary behavior and increase physical activity during productive work : a systematic review2016In: Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140, E-ISSN 1795-990X, Vol. 42, no 3, p. 181-191Article, review/survey (Refereed)
    Abstract [en]

    Objectives: Many current jobs are characterized by sedentary behaviour (SB) and lack of physical activity (PA). Interventions addressing SB and PA at the workplace may benefit workers’ health. The present review is the first to focus on the effectiveness of interventions implemented during productive work with the intention to change workers’ SB and/or PA while working.

    Methods: Scopus was searched for articles published from 1992 until March 12, 2015. Relevant studies were evaluated using the Quality Assessment Tool for Quantitative Studies and summarized in a best-evidence synthesis.

    Results: 40 studies describing 41 interventions were included and organized into three categories: alternative workstations (20), interventions promoting stair use (11) and personalized behavioural interventions (10). Strong evidence was found for alternative workstations leading to positive effects on overall SB, while evidence was conflicting for effects on SB and PA at work, overall PA, and work performance. Evidence was moderate for alternative workstations to have no effect on hemodynamics and cardiorespiratory fitness. Stair use promotion interventions were found to increase PA at work, while personalized behavioural interventions increased overall PA; both with moderate evidence. Personalized behavioural interventions were found to have no effect on anthropometric measures (moderate evidence). Regarding work performance and lipid and metabolic profiles, evidence was either conflicting or insufficient.

    Conclusions: Current evidence supports that introduction of alternative workstations may have positive effects on overall PA and SB, likely without reducing work performance, while the long-term health effects of all three reviewed categories of interventions remain to be established.

  • 105.
    Crenshaw, Albert
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Bronee, Lars
    Department of Exercise and Sports Sciences, University of Copenhagen, Copenhagen, Denmark.
    Krag, Ida
    Department of Exercise and Sports Sciences, University of Copenhagen, Copenhagen, Denmark.
    Jensen, Bente R.
    Department of Exercise and Sports Sciences, University of Copenhagen, Copenhagen, Denmark.
    Oxygenation and EMG in the proximal and distal vastus lateralis muscle during submaximal isometric knee extension2010In: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, Vol. 28, no 10, p. 1057-1064Article in journal (Refereed)
    Abstract [en]

    Muscle oxygenation responses are reportedly greater in the distal muscle region than in the proximal muscle region. We combined near infrared spectroscopy and electromyography (EMG) to determine whether regional differences in oxygenation are associated with differences in (1) muscle activation and/or (2) fatigue development. Nine males performed 2-min sustained isometric knee extensions at 15% and 30% maximum voluntary contraction during which oxygenation and EMG were recorded simultaneously from proximal and distal locations of the vastus lateralis muscle. Near infrared spectroscopy variables for oxygen saturation (StO2%) were initial slope at contraction onset, peak drop, and recovery slope at contraction end. Electromyography produced the root mean square to indicate muscle activation and mean power frequency changes over time (decreasing slope) to indicate fatigue development. For StO2%, significantly greater peak drop and steeper recovery slope were found for the distal muscle region than for the proximal muscle region. Root mean square, however, was not different between locations. Mean power frequency decreased throughout the contractions but changes were not different between locations. Our results indicate that for modest submaximal contractions, regional differences in oxygenation are not associated with differences in muscle activation or with fatigue development (as interpreted by changes in mean power frequency over time).

  • 106.
    Crenshaw, Albert
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Centre for Musculoskeletal Research.
    Svedmark, Å
    University of Gävle, Centre for Musculoskeletal Research.
    Oxygenation, EMG and position sense during computer mouse work: impact of active versus passive pauses2006In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 97, no 1, p. 59-67Article in journal (Refereed)
    Abstract [en]

    We investigated the effects of active versus passive pauses implemented during computer mouse work on muscle oxygenation and EMG of the forearm extensor carpi radialis muscle, and on wrist position sense. Fifteen healthy female subjects (age: 19-24 years) performed a 60-min mouse-operated computer task, divided into three 20 min periods, on two occasions separated by 3-6 days. On one occasion a passive pause (subjects resting) was implemented at the end of each 20-min period, and on another occasion an active pause (subjects performed a number of high intensity extensions of the forearm) was implemented. Also at the end of each 20-min period, test contractions were conducted and subjective ratings of fatigue and stress were obtained. Another parameter of interest was total haemoglobin calculated as the summation of oxy-and deoxy-haemoglobin, since it reflects blood volume changes. The most interesting findings were an overall increasing trend in total haemoglobin throughout the mouse work (P<0.001), and that this trend was greater for the active pause as compared to the passive pause (P<0.01). These data were accompanied by an overall increase in oxygen saturation (P<0.001), with a tendency, albeit not significant, toward a higher increase for the active pause (P=0.13). EMG amplitude and median frequency tended to decrease (P=0.08 and 0.05, respectively) during the mouse work but was not different between pause types. Borg ratings of forearm fatigue showed an overall increase during the activity (P<0.001), but the perceptions of stress did not change. Position sense did not change due to the mouse work for either pause type. While increasing trends were found for both pause types, the present study lends support to the hypothesis of an enhancement in oxygenation and blood volume for computer mouse work implemented with active pauses. However, a presumption of an association between this enhancement and attenuated fatigue during the mouse work was not supported.

  • 107.
    Crenshaw, Albert
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Elcadi, Guilherme
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Reproducibility and gender comparisons of oxygenation, blood flow and oxygen consumption for the forearm2010In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 42, no 5, p. 384-385Article in journal (Other academic)
  • 108.
    Crenshaw, Albert
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Fahlström, Martin
    Lyskov, Eugene
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    A gender comparison of electromyography (EMG) during repetitive arm work with and without mental stress2013In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 27, p. 1152.21-Article in journal (Other academic)
  • 109.
    Crenshaw, Albert G
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Elcadi, Guilherme H
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Forearm oxygen delivery, consumption and blood flow before and after fatigue in subjectsexperiencing work related muscle pain and healthy controls2010In: Proceedings of the Premus 2010 conference (Seventh International Conference on Prevention of Work-Related Musculoskeletal Disorders), Angers, France, 2010Conference paper (Refereed)
  • 110.
    Crenshaw, Albert G
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Elcadi, Guilherme H
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Hellström, Fredrik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Reliability of near infrared spectroscopy for measuring forearm and shoulder oxygenation in healthy males and females2012In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 112, p. 2703-2715Article in journal (Refereed)
    Abstract [en]

    This study determined the day-to-day reliability of NIRS-derived oxygenation responses (ΔStO 2%) for isometric contractions and for cuff occlusion. Twenty-four subjects (12 males and 12 females) were tested on two days (4-6 days interval). Variables generated were: (i) ΔStO 2% for isometric contractions (10%, 30%, 50% and 70% MVC) for descending trapezius (TD) and extensor carpi radialis (ECR) muscles; (ii) slope changes in total haemoglobin (HbTslope) and deoxyhaemoglobin (HHbslope) for the ECR using upper arm venous (VO, 50 mmHg) and arterial occlusion (AO, 250 mmHg); (iii) recovery slopes (Rslope) for oxygen saturation (StO2) following isometric contractions and AO. For each variable an intraclass correlation (ICC) was calculated to assess the ability to differentiate between subjects, and limits of agreement (LOA) were computed to assess day-to-day consistency of the measurement. ICCs for ΔStO2% were lowest at 10% MVC for both ECR (0.58) and TD (0.55), and highest at 30% MVC for ECR (0.95) and at 70% MVC for TD (0.79). For both muscles, LOA for ΔStO 2% was lowest at 10% and highest at 50% and 70% MVC. ICC for HbTslope was 0.17. For HHbslope ICC was higher for AO (0.83) than for VO (0.73), and LOA was lower for AO. For the ECR Rslope ICCs ranged 0.88–0.90 for contraction, but was lower for AO (0.33); LOA was lowest at 70% MVC. For trapezius Rslope ICCs ranged 0.63–0.73 and LOA was lowest at 30% MVC. For this study establishing reliability data for the ECR and TD, and including variables commonly reported, are expected to have meaning for future NIRS studies of work-related upper-extremity pain as well as for other NIRS research and clinical applications.

  • 111.
    Crenshaw, Albert G.
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Komandur, S.
    Dep of Industrial Engineering, University of Washington, Seattle.
    Johnson, P. W.
    Dep of Environmental and occupational Health Sciences, University of Washington, Seattle.
    Finger flexor contractile properties and hemodynamics following a sustained submaximal contraction: A study using electrical stimulation and near-infrared spectroscopy2010In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219, Vol. 40, no 2, p. 153-160Article in journal (Refereed)
    Abstract [en]

    We examined the effect of a low-level sustained contraction on the muscle contractile properties, hemodynamics and oxygenation of the flexor digitorum superficialis muscle (FDS) of the finger. We tested the hypothesis that hemodynamics and oxygenation, reflecting the muscle metabolic characteristics, would recovery more quickly than the muscle contractile properties. Eleven subjects (26 ± 4 yrs) were equipped with electrodes for electrical stimulation and a near-infrared spectroscopy (NIRS) probe on the forearm over the FDS. The experimental protocol consisted of three baselines measurements (-60 min, -30 min, pre-exercise), immediately after a sustained 15-min contraction of the FDS at 10% maximal voluntary contraction (post-exercise), and after 30 min, 60 min and 120 min of recovery. For each time point, participants were subjected to a battery of test that included upper arm venous occlusion (at rest), a computer-mouse point and click task (standardized voluntary task), and electrical stimulation. For venous occlusion (50 mmHg, 1 min), slopes were calculated for NIRS-derived total hemoglobin (HbTslope) and deoxyhemoglobin (HHbslope) as estimates of blood flow and oxygen consumption, respectively. The computer-mouse task entailed using the mouse to point and click on targets presented on the screen during which NIRS signals were monitored for determination of change in total hemoglobin (ΔHbT) and oxygen saturation (ΔStO2%). Electrical stimulation (2 Hz, 5 trains of 15 twitches) provided twitch force (Tw-force), contraction time (CT) and one-half relaxation time (½RT) data. Statistical analysis revealed significant changes over time for all contractile parameters as well as for HHbslope (P < 0.05 for each). Post-hoc testing demonstrated significant decreases for Tw-force post-exercise and at 60 min; for CT at post-exercise, 30 min and 60 min; and for ½RT at post-exercise and at 30 min. HHbslope was significantly higher post-exercise as compared to pre-exercise. During the computer-mouse point and click task, no significant differences were detected forΔHbT, however,ΔStO2% showed a tendency to decrease, albeit not significant (P = 0.11). Further testing showedΔStO2% was significantly lower post-exercise and at 30 min as compared to pre-exercise. The present study shows that NIRS provides insight into muscle hemodynamics and oxygenation for low-level sustained activity to fatigue. The overall quick recovery of hemodynamic and oxygenation responses, and a more prolonged recovery of contractile responses confirms our hypothesis, and this may fit well with the classical definition of low frequency fatigue.

  • 112.
    Crenshaw, Albert
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Heiden, Marina
    University of Gävle, Centre for Musculoskeletal Research.
    Lyskov, Eugene
    University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Centre for Musculoskeletal Research.
    Applying near infrared spectroscopy (NIRS) to assess muscular oxygenation during computer mouse use2007In: Sixth International Scientific Conference on Prevention of Work-Related Musculoskeletal Disorders, 2007, p. 253-Conference paper (Other academic)
    Abstract [en]

    Chronic trapezius myalgia was shown to be associated with a reduction in microcirculation (via direct measurements of bloodflow). In line with this, morphological data have indicated disturbances in oxidative metabolism. Therefore, data obtained on the muscle oxygenation status could help provide insight into the pathomechanisms behind work related muscle pain. Near-infrared spectroscopy (NIRS) allows for the noninvasive monitoring of continuous changes in skeletal muscle oxygenation (representing the dynamic balance between oxygen delivery and consumption), and for subsequent determinations of changes in blood volume.

  • 113.
    Crenshaw, Albert
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Heiden, Marina
    University of Gävle, Centre for Musculoskeletal Research.
    Lyskov, Eugene
    University of Gävle, Centre for Musculoskeletal Research.
    Johansson, Håkan
    University of Gävle, Centre for Musculoskeletal Research.
    Reduced muscular oxygenation during computer mouse use with time pressure and precision demands2004In: Conference proceedings at the American College of Sports Medicine (ACSM) 51st Annual Meeting, 2004Conference paper (Refereed)
    Abstract [en]

    Monitoring oxidative metabolic states may provide information on the mechanism behind computer use related musculoskeletal disorders. PURPOSE: To compare tissue oxygen saturation (Sat-O2) profiles in the forearm extensor carpi radialis (ECR) during computer mouse use with and without time pressure and precision demands. METHODS: Twenty-four healthy, right-handed subjects (12 females, 12 males; age 19-28 years) participated in the study. Subjects performed a 45-min mouse operated computer task on two occasions, separated by 3-5 days. The task consisted of painting squares that were presented on the screen. On one occasion, time pressure and precision demands were imposed by limiting the time available for painting a square and introducing a scoring system based on precision of painting (STRESS). On the other occasion, no such restraints were added (NON-STRESS). The order of the two task versions was randomized. During the task, Sat-O2 in the right ECR muscle was measured by near-infrared spectroscopy – NIRS (Inspectra, Hutchinson Technology). In addition, subjective ratings of tenseness and strain, and painting performance measures were recorded. RESULTS: A repeated measures ANOVA revealed a significant decline in Sat-O2 during the STRESS condition (p < 0.05), but no change for the NON-STRESS condition. A gender difference was apparent as females exhibited an overall lower Sat-O2 than males (p < 0.05); however, no interaction was found. Subjects’ ratings of tenseness and strain were significantly higher during the STRESS as compared to the NON-STRESS condition (p < 0.001). These data were paralleled by work pace (i.e. squares painted during STRESS = 119; NON-STRESS = 84, p < 0.001). Furthermore, accuracy of painting was greater for the STRESS as compared to the NON-STRESS condition (p < 0.01), i.e., number of times outside the square, STRESS = 2, NON-STRESS = 4. No gender differences in subjective ratings or performance variables were detected. CONCLUSIONS: Our finding of a change in local metabolic states under stressful conditions may shed light on the mechanism behind computer mouse related forearm muscular disorders. Furthermore, that females demonstrate a lower ECR Sat-O2 could give precedence to their higher incidence of disorders than males.

  • 114.
    Crenshaw, Albert
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Komandur, Sashidharan
    Department of Environmental and occupational Health Sciences, University of Washington, Seattle.
    Johnson, Peter W
    Department of Environmental and occupational Health Sciences, University of Washington, Seattle.
    Contractile properties and hemodynamics for a sustained submaximal contraction studied with electrical stimulation and NIRS2009In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 41, no 5, p. 220-221Article in journal (Refereed)
  • 115.
    Crenshaw, Albert
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Lyskov, Eugene
    University of Gävle, Centre for Musculoskeletal Research.
    Heiden, Marina
    University of Gävle, Centre for Musculoskeletal Research.
    Flodgren, Gerd
    University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Centre for Musculoskeletal Research.
    Hellström, Fredrik
    University of Gävle, Centre for Musculoskeletal Research.
    Physiological responses to a standardized computer mouse task: implications for pathophysiological mechanisms behind computer related disorders2007In: Work With Computing Systems - WWCS 2007, Stockholm: abstracts WWCS 2007 : Computing systems for human benefits from the 8th International Conference on Work With Computing Systems : May 21st-24th 2007, Stockholm Sweden, Stockholm: Royal Institute of Technology , 2007, p. 47-47Conference paper (Other academic)
  • 116.
    Crenshaw, Albert
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Lyskov, Eugene
    University of Gävle, Centre for Musculoskeletal Research.
    Heiden, Marina
    University of Gävle, Centre for Musculoskeletal Research.
    Flodgren, Gerd
    University of Gävle, Centre for Musculoskeletal Research. Umeå universitet.
    Hellström, Fredrik
    University of Gävle, Centre for Musculoskeletal Research.
    Impact of time pressure and pauses on physiological responses to standardized computer mouse use: a review of three papers with focusing on mechanisms behind computer-related disorders2007In: Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140, E-ISSN 1795-990X, no 3, p. 68-75Article in journal (Refereed)
    Abstract [en]

    This paper reviews three computer mouse studies in our laboratory where our emphasis was on mechanisms behind computer related disorders. Our approach was sequentially (i) to determine validity of a laboratory model of computer mouse use (painting rectangles) for studying musculoskeletal disorders; to use this model (ii) to study time pressure and precision demands on position sense and muscular oxygenation; and (iii) to determine the effect of pauses (active vs passive) on these parameters. (i) Kinematic data for the painting model showed constrained movements of the wrist similar to CAD work; a support for its validity for a real life situation. (ii) Changes in forearm oxygenation were associated with time pressure and precision demands; a potential for insight into the underlying pathophysiological mechanisms. (iii) Increasing trends in oxygenation and blood volume were associated with pauses, especially active; possible explanation for the alleviating effect of discomfort experienced in real life situations when a pause is implemented.

  • 117. Daerga, L
    et al.
    Edin–Liljegren, A
    Sjölander, Per
    University of Gävle, Centre for Musculoskeletal Research.
    Hassler, Sven
    Occupational musculoskeletal dysfunctions among reindeer herding Sami in Sweden2006In: Vaartoe: Sami research in the future, 2006Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Objectives: In a previous pilot studies it was indicated that the prevalence of musculoskeletal pain (MSP) is high among reindeer herders. The main objective of the present study was to explore potential relations between self-reported MSP, perceived dysfunction and quality of life among Swedish reindeer herding Sami, with particular emphasis on gender comparisons.

    Study Design: Cross-sectional, semi-randomised, cohort study.

    Methods: A total of 154 reindeer herders (86 men, 68 women) were offered participation in the study. They were semi-randomly selected from 7 Sami communities and represented herders who were older than 18 years of age, and belonged to households where reindeer husbandry constituted a major source of income. They answered questionnaire on pain intensity, duration and frequency in 10 separate body regions, on functional disturbances (SF-36 and Neck Disability Index), and on quality of life (in four domains - physical, social, mental and health). The questionnaires were distributed via mail to complement clinical data acquired during health examination executed by physiotherapists and GPs.

    Results: Preliminary analyses revealed a high prevalence of MSP, particularly of the back, neck, shoulder, elbows and wrists, both among men and women. Significant functional impairments and poor quality of life were reported by a majority of the participants.

    Conclusions: Detailed results and general conclusions will be presented at the conference

  • 118.
    Daerga, Laila
    et al.
    University of Gävle, Centre for Musculoskeletal Research. Southern Lapland Research Department, Vilhelmina, Sweden.
    Edin-Liljegren, Anette
    Southern Lapland Research Department, Vilhelmina, Sweden.
    Sjölander, Per
    University of Gävle, Centre for Musculoskeletal Research. Southern Lapland Research Department, Vilhelmina, Sweden.
    Quality of life in relation to physical, psychosocial and socio-economic conditions among reindeer-herding Sami2008In: International Journal of Circumpolar Health, ISSN 1239-9736, E-ISSN 2242-3982, Vol. 67, no 1, p. 8-26Article in journal (Refereed)
    Abstract [en]

    Objectives. To analyse different aspects of health-related quality of life factors among members of reindeer-herding families.

    Study design. Cross-sectional study based on data from a comprehensive survey.

    Methods. The health-related quality of life (SF-36) factors were analysed on 99 (56 men, 43 women) adult members of reindeer-herding families. Comparisons were made between the reindeer-herding family members and a Swedish reference population. Associations between mental and physical component summary measures and a number of sociodemographic, biomedical, physical, psychosocial and socio-economic variables were analysed with multivariate regression statistics.

    Results. Men scored higher than women on physical and social functioning and vitality. The average scores on the subscales for the reindeer-herding family members were similar to those of

    the Swedish reference population, except for reindeer-herding men who scored higher on physical functioning and lower on bodily pain. For women, the quality of life was related to age, sense of coherence, life-style and behavioural variables, as well as to issues such as diseases among close relatives, social networks and the economy of their business. For men, it was mainly related to musculoskeletal pain conditions, age, sense of coherence and physical and psychosocial working conditions.

    Conclusions. Men and women of the reindeer-herding families need partly different conditions to enjoy a high quality of life. From the results, it might be predicted that poor somatic and psychosocial health, increased intrusion from exploiters on the grazing land and declining profit in reindeer husbandry constitute important threats to a good quality of life among members of reindeer-herding families

  • 119.
    Dahlgren, Gunilla
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Heiden, Marina
    University of Gävle, Centre for Musculoskeletal Research.
    Crenshaw, Albert
    University of Gävle, Centre for Musculoskeletal Research.
    Lyskov, Eugene
    University of Gävle, Centre for Musculoskeletal Research.
    Johansson, Håkan
    University of Gävle, Centre for Musculoskeletal Research.
    Local oxygen saturation during computer work in patients with computer related disorders from the upper extremity: a pilot study2003In: Conference proceeding at the 49th NAM conference (Nordiska Arbetsmiljömötet), 2003Conference paper (Refereed)
    Abstract [en]

    Introduction

    Along with increasing number of computer users in work organizations, upper extremity complaints become more and more common. Research has shown that increased exposure to repetitive keyboard and mouse use increases the risk of musculoskeletal disorders. However, the physiological mechanisms remain unclear. Pathological processes as the rate of the metabolism (energy crisis) can be conceivable as a cause of the symptoms and disability related to intensive computer work 1 . To date, there are no studies made upon local tissue oxygen (O2) saturation during computer work in patients suffering from computer related disorders in the upper extremity. In the present study, we examined local tissue oxygen (O2) saturation in m. trapezius and m. extensor carpi radialis brevis before and during mouse operated computer work in patients suffering from computer related disorders, and looked at relations between oxygen saturation, subjective ratings of pain, symptoms and disability.

    Material and method

    Four right dominant female patient subjects (PS) aged 27 to 46 recruited through the company health care participated in the study. Their mean height was 166 cm and weight of three PS 55.8 kg (130 kg for the fourth PS). They had one or several diagnoses each, comprising of neck myalgia, diffuse forearm pain and lateral epicondylitis. All of them worked full-time and used computer with keyboard and mouse or mousetrapper device. Three PS used the computer for 7-8 hours per workday. The PS related their disorder to intensive computer work for long hours and high precision demands.

    Skin fold thickness was measured with a caliper at m. trapezius (TRAP) and m. extensor carpi radialis (ECRB) on the right side, and ranged from 2-6 mm. The mean skin temperature was 32.2° during rest and 32.7° following work on the ECRB (there was one missing post-value due to technical problems). The local tissue oxygen saturation was measured non-invasively with near-infrared spectroscopy, NIRS (Inspectra, Hutchinson Technology). One NIRS-electrode was placed at TRAP and the other on ECRB, both on the right side. After five minutes of rest, the PS performed a mouse operated computer task for 45 minutes with their right hand. The task consisted of painting squares presented on the screen, by using the mouse. Measurements of oxygen saturation were made throughout the computer work. Furthermore, subjective ratings of tiredness and strain were recorded on a 10 cm long VAS-scale. Symptoms and disability of the hand, arm and shoulder was rated with the DASH questionnaire, which contains the areas activities of daily living (ADL) and work 3. Descriptive statistics of the oxygen saturation comprised average and standard deviation of StO2 values in %. Comparison of the local tissue oxygen was made with the subjective ratings.

    Results and discussion

    Table 1. Local tissue oxygen (during 5 minutes rest and 45 minutes of computer work) and subjective ratings in PS.

    The mean saturation value for ECRB during rest was 52.6 (SD 20.2), work 46.7 (SD 14.7), and for TRAP during rest 58.8 (SD 21.2) and work 61.2 (SD 21.7). Skin fold thickness and skin temperature did not show any obvious interaction with the tissue oxygen values. Neither did comparisons of PS´s subjective ratings of tiredness and strain, symptoms, disability and the oxygen saturation, or severity of ratings and oxygen saturation. This might be due to the small amount of subjects and/or that the subjective ratings were not sensitive enough or do not fully reflect the state of art of computer related disorders from the upper extremity. One of the PS in our study reported intense delayed onset of pain 24 hours after the computer work. It is important to be aware that this can occur. The group of PS in this study had lower mean tissue oxygen saturation than healthy female subjects in another study that used the same device and performed an identical mouse operated computer task2. More research is needed for a better understanding of the mechanisms behind upper extremity disorders and the extent to which local tissue oxygen saturation reflects their symptoms and disability.

    References

    1. Boushel, R.; H., L.; Olesen, J.; Gonzales-Alonzo, J.; Bulow, J.; and Kjaer, M.: Monitoring tissue oxygen availability with near infrared spectroscopy (NIRS) in health and disease. Scand J Med Sci Sports, 11: 213-22, 2001.

    2. Heiden, M.; Dahlgren, G.; Lyskov, E.; Crenshaw, A.; and Johansson, H.: Effects of time pressure and precision demands during computer mouse work on muscle oxygenation and position sense. In Nordiska arbetsmiljömötet. Edited, Nyslott, Finland, 2003.

    3. http://iwh.on.ca/dash.html.

  • 120.
    Dantoft, Thomas M.
    et al.
    Danish Research Centre for Chemical Sensitivities, Copenhagen University Hospital, Gentofte, Denmark; Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark; Research Centre for Prevention and Health, Copenhagen, Denmark.
    Skovbjerg, Sine
    Research Centre for Prevention and Health, Copenhagen, Denmark.
    Andersson, Linus
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Department of Psychology, Umeå University, Umeå, Sweden.
    Claeson, Anna-Sara
    Department of Psychology, Umeå University, Umeå, Sweden.
    Engkilde, Kaare
    Department of Dermato-Allergology, National Allergy Research Center, Copenhagen University Hospital Gentofte, Denmark.
    Lind, Nina
    Department of Psychology, Umeå University, Umeå, Sweden; Department of Economics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Nordin, Steven
    Department of Psychology, Umeå University, Umeå, Sweden.
    Hellgren, Lars I.
    Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark.
    Gene expression profiling in persons with multiple chemical sensitivity before and after a controlled n-butanol exposure session2017In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 7, no 2, article id e013879Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To investigate the pathophysiological pathways leading to symptoms elicitation in multiple chemical sensitivity (MCS) by comparing gene expression in MCS participants and healthy controls before and after a chemical exposure optimised to cause symptoms among MCS participants.The first hypothesis was that unexposed and symptom-free MCS participants have similar gene expression patterns to controls and a second hypothesis that MCS participants can be separated from controls based on differential gene expression upon a controlled n-butanol exposure.

    DESIGN: Participants were exposed to 3.7 ppm n-butanol while seated in a windowed exposure chamber for 60 min. A total of 26 genes involved in biochemical pathways found in the literature have been proposed to play a role in the pathogenesis of MCS and other functional somatic syndromes were selected. Expression levels were compared between MCS and controls before, within 15 min after being exposed to and 4 hours after the exposure.

    SETTINGS: Participants suffering from MCS and healthy controls were recruited through advertisement at public places and in a local newspaper.

    PARTICIPANTS: 36 participants who considered themselves sensitive were prescreened for eligibility. 18 sensitive persons fulfilling the criteria for MCS were enrolled together with 18 healthy controls.

    OUTCOME MEASURES: 17 genes showed sufficient transcriptional level for analysis. Group comparisons were conducted for each gene at the 3 times points and for the computed area under the curve (AUC) expression levels.

    RESULTS: MCS participants and controls displayed similar gene expression levels both at baseline and after the exposure and the computed AUC values were likewise comparable between the 2 groups. The intragroup variation in expression levels among MCS participants was noticeably greater than the controls.

    CONCLUSIONS: MCS participants and controls have similar gene expression levels at baseline and it was not possible to separate MCS participants from controls based on gene expression measured after the exposure.

  • 121.
    Dantoft, Thomas
    et al.
    Danish Research Centre for Chemical Sensitivities, Copenhagen University Hospital, Gentofte, Denmark; Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark; Research Centre for Prevention and Health, Copenhagen, Denmark.
    Skovbjerg, Sine
    Research Centre for Prevention and Health, Copenhagen, Denmark.
    Andersson, Linus
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Department of Psychology, Umeå University, Umeå, Sweden.
    Claeson, Anna-Sara
    Department of Psychology, Umeå University, Umeå, Sweden.
    Engkilde, Kaare
    Department of Dermato-Allergology, The National Allergy Research Center, Copenhagen University Hospital Gentofte, Denmark.
    Lind, Nina
    Department of Psychology, Umeå University, Umeå, Sweden; Department of Economics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Nordin, Steven
    Department of Psychology, Umeå University, Umeå, Sweden.
    Hellgren, Lars I.
    Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark.
    Gene expression profiling in MCS before and upon a controlled symptom eliciting n-butanol exposure: a pilot study2017In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 7, no 2, article id e01387Article in journal (Refereed)
    Abstract [en]

    Objectives To investigate the pathophysiological pathways leading to symptoms elicitation in multiple chemical sensitivity (MCS) by comparing gene expression in MCS participants and healthy controls before and after a chemical exposure optimised to cause symptoms among MCS participants.

    The first hypothesis was that unexposed and symptom-free MCS participants have similar gene expression patterns to controls and a second hypothesis that MCS participants can be separated from controls based on differential gene expression upon a controlled n-butanol exposure.

    Design Participants were exposed to 3.7 ppm n-butanol while seated in a windowed exposure chamber for 60 min. A total of 26 genes involved in biochemical pathways found in the literature have been proposed to play a role in the pathogenesis of MCS and other functional somatic syndromes were selected. Expression levels were compared between MCS and controls before, within 15 min after being exposed to and 4 hours after the exposure.

    Settings Participants suffering from MCS and healthy controls were recruited through advertisement at public places and in a local newspaper.

    Participants 36 participants who considered themselves sensitive were prescreened for eligibility. 18 sensitive persons fulfilling the criteria for MCS were enrolled together with 18 healthy controls.

    Outcome measures 17 genes showed sufficient transcriptional level for analysis. Group comparisons were conducted for each gene at the 3 times points and for the computed area under the curve (AUC) expression levels.

    Results MCS participants and controls displayed similar gene expression levels both at baseline and after the exposure and the computed AUC values were likewise comparable between the 2 groups. The intragroup variation in expression levels among MCS participants was noticeably greater than the controls.

    Conclusions MCS participants and controls have similar gene expression levels at baseline and it was not possible to separate MCS participants from controls based on gene expression measured after the exposure

  • 122.
    Degerstedt, Frida
    et al.
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden; Umeå Center for Gender Studies, Umeå University, Umeå, Sweden.
    Enberg, Birgit
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Keisu, Britt-Inger
    Umeå Center for Gender Studies, Umeå University, Umeå, Sweden.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational Health Science and Psychology, Occupational Health Science. University of Gävle, Centre for Musculoskeletal Research. Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Inequity in physiotherapeutic interventions for children with Cerebral Palsy in Sweden - a national registry study.2019In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227Article in journal (Refereed)
    Abstract [en]

    AIM: The aim of this study was to investigate the distribution of physiotherapeutic interventions for children with Cerebral Palsy in Sweden from an equity perspective, considering sex, country of birth and geographical region.

    METHOD: This national cross-sectional registry study includes children with Cerebral Palsy aged 0-18 years who participated in 2015 in the Swedish national quality registry, the Cerebral Palsy follow-up program, CPUP. Comparisons and associations between physiotherapeutic interventions and sex, country of birth and geographical regions were conducted using Chi2 and logistic regression analysis, controlling for cognitive level, level of motor function, age group and dominating symptom.

    RESULTS: Of the 2855 participants, 2201 (79%) had received physiotherapy. Children born in Sweden had 1.60 times higher odds (95% CI 1.10-2.33) of receiving physiotherapy compared with children born in foreign countries. Distribution of physiotherapeutic interventions differed significantly between geographical regions. No associations between sex and physiotherapeutic interventions were observed.

    CONCLUSION: The results of this study indicate inequity in care in Sweden towards children with Cerebral Palsy born in other counties. Further, physiotherapeutic interventions were not equally distributed in different.

  • 123. Dempsey, P G
    et al.
    Mathiassen, Svend Erik
    University of Gävle, Centre for Musculoskeletal Research.
    Jackson, Jennie A
    Influence on work pace conditions on temporal organization of work and rest2006In: Meeting diversity in ergonomics: proceedings IEA 2006 Congress / [ed] Pikar, R.N. et al, 2006Conference paper (Other academic)
    Abstract [en]

    A study was conducted to investigate the influence of different approaches to arranging the pace and temporal organization of repetitive assembly and disassembly tasks on variability in performance, and to compare assembly and disassembly times derived with psychophysical methods to more traditional Methods- Time Measurement (MTM) approaches. The conditions studied were a traditional assembly line arrangement where assemblies were started at a pace of 110 MTM, a batch condition where subjects were required to complete 36 assemblies in the amount of time based on 110 MTM, a line condition where subjects were required to take a break after every 6 assemblies requiring theffi to work at a 120 MTM pace, and a psychophysical condition where subjects were allowed to choose their pace.

    Overall, the results suggest that the mean times spent working remained fairly constant a cross conditions, with more variation in pauses in between cycles. For the second self-paced condition, subjects selected a significantly higher pace than 1 10 MTM, which was the basis for the other conditions. The higher pace was achieved through reduction in mean pauses, and the potential implications for musculoskeletal risk are discussed.

  • 124.
    Dempsey, Patrick G
    et al.
    Liberty Mutual Research Institute for Safety, Center for Safety Research, Hopkinton, MA, United States .
    Mathiassen, Svend Erik
    University of Gävle, Centre for Musculoskeletal Research. Liberty Mutual Research Institute for Safety, Center for Safety Research, Hopkinton, MA, United States .
    On the evolution of task-based analysis of manual materials handling, and its applicability in contemporary ergonomics2006In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 37, no 1, p. 33-43Article in journal (Refereed)
    Abstract [en]

    The industrial revolution significantly changed the way work was organized and analyzed by the introduction and widespread implementation of the division of labor philosophy. This philosophy has continued to dominate work design, and has evolved beyond the factory to include many facets of service industries, and even professional occupations. The analysis of manual work, particularly materials handling tasks, remains an active domain of ergonomics research and practice. Many of the task-analytic tools used for workplace analysis are rooted in the philosophy of dividing work into elements, analyzing the individual elements, and synthesizing the results into conclusions about the entire job, including the risk of contracting musculoskeletal disorders (MSDs). The authors discuss the notion that the nature of modern work, which is characterized by multiple tasks in a complex time pattern, and the complex nature of MSDs, which are influenced by biomechanical as well as psychological, political, and economic factors, may limit the effectiveness of classical task analytic techniques in preventing MSDs.

  • 125.
    Dempsey, Patrick G.
    et al.
    Liberty Mutual Research Institute for Safety, Massachusetts, USA.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Jackson, Jennie A.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    O'Brien, Niall V
    Liberty Mutual Research Institute for Safety, Hopkinton MA, USA.
    Influence of three principles of pacing on the temporal organisation of work during cyclic assembly and disassembly tasks2010In: Ergonomics, ISSN 0014-0139, E-ISSN 1366-5847, Vol. 53, no 11, p. 1347-1358Article in journal (Refereed)
    Abstract [en]

    A study was conducted to investigate the influence of different approaches to arranging the pace and temporal organisation of repetitive assembly and disassembly tasks on both average performance and its variability and to compare assembly and disassembly times derived with psychophysical methods to a more traditional methods-time measurement (MTM) approach. The conditions studied were a traditional assembly line arrangement, where assemblies were started at a pace of 110 MTM (repeated on two occasions), a batch condition, where subjects were required to complete 36 assemblies within the total amount of time allowed at 110, MTM and a psychophysical condition, where subjects were allowed to choose their pace (repeated on two occasions). Overall, the results suggest that the mean time spent working in each cycle (the 'on-time') remained fairly constant across conditions, while the idle 'off-time' in between on-times was shorter and of less varied duration in the more autonomous batch and psychophysical conditions. During the second psychophysical (self-paced) condition, subjects completed a significantly higher number of assemblies than during the 110 MTM line condition. The higher pace was achieved through reduction in mean off-times and the potential implications for musculoskeletal risk are discussed. Statement of Relevance: Higher levels of autonomy over work pace, which intuitively would be beneficial from an ergonomics standpoint, actually led to subjects selecting to organise work such that off-times (idle times) were reduced. In contrast, active 'on' times were not affected much by autonomy. These results point to a reason that piecework would be associated with increased risk for musculoskeletal disorders.

  • 126.
    Djupsjöbacka, Mats
    University of Gävle, Centre for Musculoskeletal Research.
    Ospecifika muskuloskeletala besvär: rehabilitering, behandling och träning av senmotorisk funktion2007In: Svensk Rehabilitering, ISSN 1403-4468, Vol. 8/9, no 4-1, p. 26-29Article in journal (Refereed)
    Abstract [en]

    Långvarig värk i nacke-skuldra och ländrygg tillhör de vanligaste orsakerna till sjukskrivning. Bakgrunden till dessa tillstånd är vanligen oklara, vilket gör att kausal behandling inte är aktuell. Senare års forskning visar dock att multimodal rehabilitering ger god effekt och är kostnadseffektiv. Forskningen ger även en god grund för att träning av sensomotorisk funktion kan vara effektiv vid dessa tillstånd.

  • 127.
    Djupsjöbacka, Mats
    University of Gävle, Centre for Musculoskeletal Research.
    Proprioception and neck/shoulder pain2008In: Fundamentals of musculoskeletal pain, Seattle: IASP Press , 2008, p. 385-399Chapter in book (Other academic)
    Abstract [en]

    Chronic neck/shoulder pain constitutes an extensive health problem. The point prevalence has been estimated to be as high as 18% in the general population (Guez et al., 2003). The symptoms usually involve pain and stiffness in the neck/shoulder area as well as impaired neck mobility. A history of neck or head trauma is rather common. Thus, in the population studied by Guez et al. (2003), more than one fourth of the cases had a history of such trauma. Nevertheless, due to a limited knowledge on the underlying pathomechanisms, the source of the symptoms can only rarely be established. This obviously poses a severe problem for efficient treatment and rehabilitation of this patient group.

    In order to improve treatment and rehabilitation it is thus important to develop sensitive and specific methods for characterization of patients with chronic neck/shoulder pain. This should obviously entail many different aspects of the patient characteristics. One such aspect that has received increasing attention is sensorimotor functions, for example muscle coordination and proprioception. The growing interest in this area is based on an increasing number of studies reporting atypical, or impaired, sensorimotor functioning in subjects with chronic neck/shoulder pain, along with the fact that several models on the pathophysiology behind musculoskeletal disorders involves various aspects of sensorimotor functioning.

    This chapter will deal with one of these sensorimotor functions: proprioception. First, a background to the topic and a review on the research on proprioception in relation to chronic neck/shoulder pain is given, along with a discussion on methodology. Lastly, implications for future research as well as clinical implications are discussed.

  • 128.
    Djupsjöbacka, Mats
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Björklund, Erika
    University of Gävle, Faculty of Education and Business Studies, Department of Educational sciences, Educational science, Education.
    Nordlöf, Hasse
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Utveckling av arbetsmiljöutbildning på yrkesgymnasium för förebyggande av belastningsbesvär och främjandet av ett hållbart arbetsliv för installationselektriker: En förberedande fallstudie2018In: FALF KONFERENS 2018. Arbetet - problem eller potential för en hållbar livsmiljö? Gävle 10-12 juni 2018: Program och Abstracts / [ed] Per Lindberg, Gävle: Gävle University Press , 2018, p. 92-Conference paper (Refereed)
    Abstract [sv]

    Bakgrund och syfte

    Många yrkesprogram på gymnasiet utbildar för yrken där vi vet att anställda ofta drabbas av belastningsrelaterad ohälsa. Exempelvis visar data från Arbetsmiljöverket att 9–12% av alla installationselektriker och elmontörer rapporterar besvär orsakade av påfrestande arbetsställningar och att de rapporterar en ettårsprevalens på 6–10% för besvär i nacke, axlar, arm och rygg till följd av arbetet som varit så svåra att det påverkat arbetsförmågan. Forskning har även visat att elever på elteknikprogram löper särskilt hög risk att drabbas av arbetsskada relativt andra utbildningar. Redan under utbildningen bör åtgärder sättas in för att minska dessa risker.

    En genomgång av litteraturen visar dock att det finns tydliga brister i hur yrkesprogram förbereder eleverna för ett kommande arbetsliv vad gäller arbetsmiljökunskap och att orsakerna till dessa brister troligen finns inom undervisningens innehåll och utformning, lärares kompetens och samverkan med yrkeslivet under utbildningen. Vidare kan elever-nas attityder till arbetsmiljöundervisning utgöra ett hinder. Sammantaget förefaller hin-dren för en bra arbetsmiljöutbildning på yrkesprogram inom gymnasiet vara komplexa och multifaktoriella.

    Innan åtgärder sätts in för att utveckla undervisningen finns därför stort behov av att kartlägga de komplexa orsakssambanden bakom brister inom utbildningen och utifrån det utforma förbättringsåtgärder.

    I vår studie avser vi att svara på forskningsfrågan: Hur anser olika intressenter att olika faktorer inom såväl utbildningen som framtida yrkeskontext interagerar och bidrar till uppkomsten av belastningsbesvär hos installationselektriker?

    Metod och resultat

    Studien har en fallstudiedesign där fokusgrupper och problemträdsanalys används. Pro-blemträdsanalys är en metod för att kartlägga komplexa orsakssamband och att klargöra grundläggande orsaker. Analysen kan därmed säkra att aktiviteter och insatser inte väljs och påbörjas utan att man först har kartlagt kärnproblemets ofta komplexa orsaker grundligt.

    Som underlag till problemträdsanalysen kommer fokusgruppsintervjuer att genomföras där personer från samma kategori intressenter separat samtalar om kärnproblemet. Vi kommer genomföra intervjuer separat med elever, lärare, skolledning och representanter från arbetslivet. Problemträdsanalysen genomförs sedan vid ett tillfälle där 2–3 personer från varje intressent; elever, lärare, skolledningen, representanter från arbetslivet och forskare från projektgruppen deltar. Inför sessionen kommer vi att delge deltagarna underlag baserat på resultaten från fokusgruppintervjuerna och vår litteratursökning så att de kan ta del avSession D:2Individuella presentationer: Fysiskt arbetsliv93vad andra intressegrupper/källor identifierat som möjliga orsaksfaktorer. Efter framtagande av problemträd kommer tänkbara lösningar att formuleras i samverkan med alla intressenter för att skapa ett lösningsträd, vilket kommer att utgöra grund för kommande utvecklingsarbete inom utbildningen.

    Datainsamling och analyser genomförs under våren 2018 och preliminära resultat kommer att presenteras på konferensen.

  • 129.
    Djupsjöbacka, Mats
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Röiijezon, Ulrik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Häger-Ross, Charlotte
    Ortopedkliniken, Norrlands universitetssjukhus, Umeå.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Sensomotorisk funktion hos personer med nackbesvär2010In: Fysioterapi, ISSN 1653-5804, no 6-7, p. 38-45Article, review/survey (Other academic)
    Abstract [en]

    Nackbesvär är vanligt förekommande och utgör en betydande orsak till ohälsa och inskränkt arbetsförmåga. Vanligen går det inte att klarlägga organisk orsak till långvariga nackbesvär men mycket tyder på att de oftast är ett komplext tillstånd där både biologiska och psykosociala faktorer är av betydelse. Forskning har visat på samband mellan långvariga nackbesvär och störningar i olika sensomotoriska funktioner och att graden av funktionspåverkan ofta är kopplad till graden av upplevda besvär. Undersökning av sensomotorisk funktion kan därför vara en viktig del i bedömningen av denna patientgrupp. Forskning har även visat att det finns evidens för positiva effekter av sensomotorisk träning vid nackbesvär på kort sikt, medan kunskap om långtidseffekter saknas. Vid träning av sensomotorisk funktion är det viktigt att beakta grundläggande kunskap inom motorisk inlärning för att öka möjligheterna till bestående träningseffekter och att dessa överförs till vardagliga situationer.

  • 130.
    Domkin, Dmitry
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Richter, Hans
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Ciliary muscle contraction force and trapezius muscle activity during manual tracking of a moving visual target2016In: Journal of Electromyography & Kinesiology, ISSN 1050-6411, E-ISSN 1873-5711, Vol. 28, p. 193-198Article in journal (Refereed)
    Abstract [en]

    Previous studies have shown an association of visual demands during near work and increased activity of the trapezius muscle. Those studies were conducted under stationary postural conditions with fixed gaze and artificial visual load. The present study investigated the relationship between ciliary muscle contraction force and trapezius muscle activity across individuals during performance of a natural dynamic motor task under free gaze conditions. Participants (N = 11) tracked a moving visual target with a digital pen on a computer screen. Tracking performance, eye refraction and trapezius muscle activity were continuously measured. Ciliary muscle contraction force was computed from eye accommodative response. There was a significant Pearson correlation between ciliary muscle contraction force and trapezius muscle activity on the tracking side (0.78, p < 0.01) and passive side (0.64, p < 0.05). The study supports the hypothesis that high visual demands, leading to an increased ciliary muscle contraction during continuous eye–hand coordination, may increase trapezius muscle tension and thus contribute to the development of musculoskeletal complaints in the neck–shoulder area. Further experimental studies are required to clarify whether the relationship is valid within each individual or may represent a general personal trait, when individuals with higher eye accommodative response tend to have higher trapezius muscle activity.

  • 131.
    Domkin, Dmitry
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    Division of Occupational and Environmental Medicine, Department of Public Health Sciences, Karolinska Institute.
    Richter, Hans
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Relationship between eye-lens accomodative response and trapezius muscle activity during manual tracking of a visual target2014In: 11th International Symposium on Human Factors in Organisational Design and Management (ODAM 2014)and 46th Annual Nordic Ergonomics Society, Technical University of Denmark , 2014, p. 1073-1074Conference paper (Refereed)
  • 132.
    Domkin, Dmitry
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational Health Science. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.; KTH Royal Institute of Technology, Stockholm, Sweden.
    Richter, Hans O.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational Health Science. University of Gävle, Centre for Musculoskeletal Research.
    Effect of ciliary-muscle contraction force on trapezius muscle activity during computer mouse work2019In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 119, no 2, p. 389-397Article in journal (Refereed)
    Abstract [en]

    The present study aimed to identify whether or not an increase in ciliary-muscle contraction force, when the eye-lens is adjusted for viewing at a near distance, result in an increase in trapezius muscle activity, while performing a natural work task. Twelve participants, ranging in age from 21 to 32 years, performed a computer-mouse work task during free gaze conditions. A moving visual target was tracked with a computer mouse on a screen placed at two different distances from the eyes, 25 cm and 50 cm. Tracking performance, eye accommodation, and bilateral trapezius muscle activity were measured continuously. Ciliary-muscle contraction force was computed according to a formula which takes into account the age-dependent, non-linear relationship between contraction force of the ciliary muscle and the produced level of eye accommodation. Generalized Estimating Equations analyses were performed. On the dominant hand side and for the nearest screen distance, there was a significant effect of ciliary-muscle contraction force on the trapezius muscle activity (p<0.001). No other effects were significant (p>0.05). The results support the hypothesis that high visual demands, during computer mouse work, increase ciliary muscle contraction force and contribute to a raise of the sustained level of trapezius muscle activity. The current study specifically clarifies the validity of the relationship between ciliary-muscle contraction force and trapezius muscle activity and demonstrates that this relationship is not due to a general personal trait. We conclude that a high level of ciliary muscle contraction force can contribute to a development of musculoskeletal complaints in the neck-shoulder area.

  • 133.
    Domkin, Dmitry
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Richter, Hans
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Zetterlund, Christina
    Örebro County Council, Örebro, Sweden; Örebro University, Örebro, Sweden.
    Lundqvist, Lars-Olov
    Örebro County Council, Örebro, Sweden; Örebro University, Örebro, Sweden.
    Effect of reduced visual acuity on precision of two-dimensional tracing movements2016In: Journal of Optometry, ISSN 1888-4296, Vol. 9, no 2, p. 93-101Article in journal (Refereed)
    Abstract [en]

    Purpose

    We intended to assess consequences of reduced visual acuity for performance in a natural simple motor task (tracing) using objective kinematic performance measures. Specifically, we intended to elucidate the kind of relationship between the task performance and best corrected binocular visual acuity and to determine the threshold of visual acuity when task performance starts to deteriorate.

    Methods

    Ninety-five individuals with different best corrected visual acuity participated in the study (age 49 ± 12 years, mean ± SD, 27 men and 68 women). The participants manually traced maze-like visual patterns of different spatial complexity presented on the screen of a portable notebook computer using Clinical Kinematic Assessment Tool software. Tracing error was computed as performance measure in each trial with a spatial pattern matching technique – rigid point set registration method.

    Results

    The segmented linear regression analysis showed that the relation between visual acuity and tracing errors was best described with a regression function having a break point between two data segments. Tracing performance was unaffected by values of visual acuity below 0.2 on logMAR scale, but when logMAR values increased above this critical limit (i.e. when visual acuity is further reduced), tracing errors linearly increased. The rate of the increase of the tracing error correlated with the complexity of visual stimulus shape.

    Conclusion

    Testing of fine motor functions with objective kinematic measures during visuomotor tasks may help differentiating between actual effects of reduced visual acuity on eye–hand coordination in individuals with similar levels of impairment of visual acuity.

  • 134.
    Domkin, Dmitry
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Sörqvist, Patrik
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - applied psychology.
    Richter, Hans
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Distraction of Eye-Hand Coordination varies with Working Memory Capacity2013In: Journal of motor behavior, ISSN 0022-2895, E-ISSN 1940-1027, Vol. 45, no 1, p. 79-83Article in journal (Refereed)
    Abstract [en]

    The authors present a study of the relationship between individual variation in working memory capacity (WMC) and visually guided hand control in the face of visual distraction. WMC was assessed with the automated operation span task. Hand control was measured by requesting participants to track a visual target with a hand-held touch screen pen. Tracking error increased when nontarget visual objects (distractors) appeared, especially in individuals with low WMC. High-WMC individuals are less impaired by distractors than their low-WMC counterpart, because they resume target tracking more quickly after distractor onset. The results suggest that visual distractors cause a momentary interruption to tracking movements and that high WMC attenuates this interruption by facilitating visual search.

  • 135. Dragasevic, N T
    et al.
    Radovanovic, Sasa
    University of Gävle, Centre for Musculoskeletal Research.
    Maric, J
    Svetel, M
    Petrovic, I
    Kostic, V S
    Cortical excitability revealed by motor evoked potential, cortical silent period and conduction time in spinocerebellar ataxias type 1, type 2 and idiopathic sporadic cerebellar ataxia: a transcranial magnetic stimulation study2006In: The Movement Disorder Society’s 10th International Congress of Parkinson’s Disease and Movement: October 28 - November 2, Kyoto, Japan, 2006Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Autosomal dominant cerebellar ataxias are characterized by their underlying genetic defect and are referred to as spinocerebellar ataxias (SCAs 1-23). The clinical classification of the SCA has been difficult owing to variations and overlapping of the clinical signs. The aim of this study was to compare cortical motor evoked potential (MEP), central motor conduction time (CMCT) and cortical silent period (CSP) duration in SCA patients in Serbia, namely in genetically  homogenous groups of ataxia patients with type 1, type 2 and IDCA (idiopathic sporadic cerebellar ataxia).

    We examined 29 patients, 16 with the diagnosis of SCA 1, 6 SCA 2 and 7 IDCA patients. Eight healthy control subjects were gender and age matched. Transcranial magnetic stimulation (TMS) was used to investigate parameters of cortical excitability such as: motor threshold (MT) and MEP, CSP and CMCT. MT was established at rest, MEP was calculated as the area in the rectified EMG recording. CSP was evoked by 30% suprathreshold stimulation while subjects activated FDI muscle with contraction of 30% of their MVC. CMCT was calculated as a difference between the shortest MEP latency after cortical and after cervical stimulation (in the region of C5-C6).

    Results show that MT was increased in all ataxia patient groups, compared to control subjects. CMCT has significant increase in SCA 1 patients. CSP in IDCA patients is significantly longer then in SCA 1, SCA 2 and control subjects, while no difference was found between SCA 1, SCA 2 and control. MEP duration was significantly increased in all ataxia groups compared to control in relaxed muscle.

    Due to the cerebellar influence on the cortico-spinal system through control of inhibitory cortical interneurons, could be assumed that different categories of ataxia patients have disturbed cerebellar inhibitory influence to the various degrees. It might be possible that SCA 1 prominent abnormalities in cortical excitability originate from expansion of damage from cerebellum to some other cerebellar and brain structures.

  • 136.
    Dropkin, Jonathan
    et al.
    Department of Department of Occupational Medicine, Epidemiology, and Prevention, Hofstra North Shore-LIJ School of Medicine, USA.
    Moline, Jacqueline
    Department of Occupational Medicine, Epidemiology, and Prevention, Hofstra North Shore-LIJ School of Medicine, USA.
    Kim, Hyun
    Department of Occupational Medicine, Epidemiology, and Prevention, Hofstra North Shore-LIJ School of Medicine, USA.
    Gold, Judith
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Blended work as a bridge between traditional workplace employment and retirement: a conceptual review2016In: Work, Aging and Retirement, ISSN 2054-4642, E-ISSN 2054-4650, Vol. 2, no 4, p. 373-383Article, review/survey (Refereed)
    Abstract [en]

    Because of population aging, the consensus among policy makers is that employment in older workers must increase. However, methods for attaining this are uncertain. Blended work, which consists of working anywhere and any-time with information and communication technology, may help achieve this goal. The article focuses on 4 top-ics related to older workers and blended work: the benefits, risks, individual- and organizational-level barriers, and organizational and government interventions and policies designed to remove these risks and barriers. Legislation to protect against age discrimination and disability associated with age is also reviewed. The objectives are to dis-cuss the literature on blended work and the older worker and highlight some consequences the Age Discrimination in Employment Act and American with Disabilities Act may have on blended work. Delaying retirement through blended work could promote older workers’ health and well-being, but risks and barriers at individual- and organi-zational-levels are not inconsequential. At the individual level, these include social isolation, and managements’ loss of control over employees at the organizational level. Potential interventions include developing blended work as an employee benefit to replace long distance travel. Federal policies include providing subsidies to state and local gov-ernments to reduce costs of upgrading broadband fiber-optic cables. Specific subgroups of workers are more likely to benefit from blended work. Older white collar professionals with good technological and computer skills and who can work independently are one subgroup that might fit a blended worker personality.

  • 137. Edin-Liljegren, A
    et al.
    Hassler, Sven
    Sjölander, Per
    University of Gävle, Centre for Musculoskeletal Research.
    Daerga, L
    Psychosocial risk factors among Sami in Sweden: a controlled cohort study2006In: Vaartoe: Sami research in the future, 2006Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Objective: To investigate the occurrence of psychosocial, clinical and behavioural risk factors for cardiovascular diseases (CVD) among reindeer herding and non-reindeer herding Sami. The results on psychosocial risk factors are presented here.

    Materials and Methods: A cohort of 611 Swedish Sami (276 men and 335 women) was constructed from national population registers and compared with a twice as large control population of non-Sami, matched by age, gender and area of residency. Information on quality of life, social support and Karasek and Theorell`s job-strain indices was obtained from a database containing information from a regional CVD-preventive program. The data was collected from the period of 1990–2001.

    Results: The Sami people reported lower quality of life and higher demand and intellectual discretion at work than the non-Sami. The Sami women, the reindeer herding as well as the non-reindeer herding, had lower scores on intellectual discretion and social support at work compared with the Sami men.

    Conclusions: Regarding the psychosocial risk factors investigated here it seems that the Sami women are at higher risk than the Sami men.

  • 138.
    Edvinsson, Johanna
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Jahncke, Helena
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Development and validation of a questionnaire addressing flexible work and restoration2017Conference paper (Refereed)
  • 139.
    Elcadi, Guilherme
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    Public Health Sciences, Karolinska institute, Stockholm.
    Aasa, Ulrika
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University.
    Fahlström, Martin
    Department of Community Medicine and Rehabilitation, Rehabilitation Medicine, Umeå University.
    Crenshaw, Albert
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Shoulder and forearm oxygenation and myoelectric activityin patients with work-related muscle pain and healthy subjects2013In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 113, no 5, p. 1103-1115Article in journal (Refereed)
  • 140.
    Elcadi, Guilherme
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    Karolinska institutet.
    Crenshaw, Albert
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Oxygenation and myoelectric activity in the forearm and shoulder muscles of males and females2010In: MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, ISSN 0195-9131, Vol. 42, no 5, p. 384-384, article id 1745Article in journal (Other academic)
  • 141.
    Elcadi, Guilherme
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research. Occupational and Environmental Medicine, Public Health Sciences, Stockholm, Sweden.
    Crenshaw, Albert
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    The relationship between myoelectric activity and oxygenation during isometric contractions in the forearm and shoulder muscles of healthy males and females2010In: The XVIII Congress of the International Society of Electrophysiology and Kinesiology (ISEK), 2010Conference paper (Refereed)
  • 142.
    Elcadi, Guilherme
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Department of Community Medicine and Rehabilitation, Rehabilitation medicine, Umeå University, Umeå, Sweden.
    Forsman, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
    Hallman, David
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Aasa, Ulrika
    5 Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Fahlström, Martin
    Department of Community Medicine and Rehabilitation and Department of Clinical Sciences, Umeå University, Umeå, Sweden .
    Crenshaw, Albert
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Oxygenation and hemodynamics do not underlie early muscle fatigue for patients with work-related muscle pain2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 4, p. e95582-Article in journal (Refereed)
    Abstract [en]

    Patients suffering from work-related muscle pain (WRMP) fatigue earlier during exercise than healthy controls. Inadequate oxygen consumption and/or inadequate blood supply can influence the ability of the muscles to withstand fatigue. However, it remains unknown if oxygenation and hemodynamics are associated with early fatigue in muscles of WRMP patients. In the present study we applied near-infrared spectroscopy (NIRS) on the extensor carpi radialis (ECR) and trapezius (TD) muscles of patients with WRMP (n = 18) and healthy controls (n = 17). Our objective was to determine if there were group differences in endurance times for a low-level contraction of 15% maximal voluntary contraction (MVC) – sustained for 12-13 min, and to see if these differences were associated with differences in muscle oxygenation and hemodynamics. At baseline, oxygen saturation (StO2%) was similar between groups for the ECR, but StO2% was significantly lower for TD for the WRMP patients (76%) compared to controls (85%) (P < 0.01). Also, baseline ECR blood flow was similar in the two groups. For both muscles there were a larger number of patients, compared to controls, that did not maintain the 15% MVC for the allotted time. Consequently, the endurance times were significantly shorter for the WRMP patients than controls (medians, ECR: 347 s vs. 582 s; TD: 430 s vs. 723 s respectively). Responses in StO2% during the contractions were not significantly different between groups for either muscle, i.e. no apparent difference in oxygen consumption. Overall, we interpret our findings to indicate that the early fatigue for our WRMP patients was not associated with muscle oxygenation and hemodynamics.

  • 143.
    Elcadi, Guilherme H
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    Occupational and Environmental Medicine, Public Health Sciences, Institute Karolinska, Stockholm, Sweden.
    Crenshaw, Albert G
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Gender differences in the forearm for the oxygenation and myoelectric activity relation, muscle blood flow and oxygen consumption2010In: Proceedings of the Premus 2010 conference, Angers, France, 2010Conference paper (Refereed)
  • 144.
    Elcadi, Guilherme H
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research. University of Umeå, Sweden .
    Forsman, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research. Karolinska Institutet, Stockholm, Sweden .
    Crenshaw, Albert G
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    The relationship between oxygenation and myoelectric activity in the forearm and shoulder muscles of males and females2011In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 111, no 4, p. 647-58Article in journal (Refereed)
    Abstract [en]

    The aim was to investigate the relationship between oxygen saturation (StO(2)%) measured with near-infrared spectroscopy (NIRS) and myoelectric activity (root mean square, RMS) for the extensor carpi radialis (ECR) and trapezius muscles. In addition, gender differences were examined for submaximal (10-70% MVC) and sustained (10% MVC for 5 min) isometric contractions. Thirteen males and 15 females participated. Changes in StO(2)% (∆StO(2)%) and RMS, expressed as percentages of maximum, were calculated for each submaximal contraction. A good correlation between ∆StO(2)% and RMS was seen for the ECR (r = -0.53) and a moderate correlation seen for the trapezius muscle (r = -0.44). The ANOVA showed a significant decrease in ECR-∆StO(2)% over force with females demonstrating a tendency for larger changes than males. ECR-RMS increased over force with no impact of gender. For the trapezius, ∆StO(2)% decreased over force but was not gender dependent. Trapezius-RMS increased over force with females demonstrating a tendency for greater change than males. For the sustained contraction, ECR-StO(2)% changed over time but was not gender dependent. ECR-RMS increased over time with females showing a greater response than males. Trapezius-StO(2)% changed over time and differed between genders, i.e., males increased while females decreased. RMS increased over time similarly for both genders. In conclusion, our data show that the ECR and trapezius aerobic demands during isometric contractions are negatively correlated to electromyography (EMG) RMS. The present study also suggests some gender specificity for forearm and shoulder myoelectric activity and oxygenation for submaximal and sustained contractions.

  • 145.
    Elcadi, Guilherme H.
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Health and Caring Sciences, Sports science.
    Tsaklis, Panagiotis
    Alexander Technological Institute of Thessaloniki, Thessaloniki, Greece.
    Blomqvist, Sven
    University of Gävle, Faculty of Health and Occupational Studies, Department of Health and Caring Sciences, Sports science.
    Ervasti, Per-Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Health and Caring Sciences, Sports science.
    W. Söderström, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Health and Caring Sciences, Sports science.
    Forsman, Mikael
    Karolinska Institute, Stockholm, Sweden.
    Richter, Hans
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    A Strong Correlation Between Dorsolateral Prefrontal Cortex And Vastus Lateralis Activity During Running To Fatigue2016In: Medicine and science in sports and exercise, ISSN 0195-9131, Vol. 48, no 5, p. 854-854Article in journal (Refereed)
    Abstract [en]

    Fatigue is a phenomenon of pronounced importance in sports. Recently, there is strong evidence of interplay between the prefrontal cortex and motor output during fatiguing contractions. The dorsolateral prefrontal cortex (DLPC) due to its large involvement in cognitive and motor activities is believed to be involved but this requires physiological clarification. AIM: We investigated the relationship between DLPC activity - responses in oxyhemoglobin (HbO2) and total hemoglobin (HbT) measured by near-infrared spectroscopy (NIRS), and the vastus lateralis muscle (VL) activity - quantified as root-mean-square (RMS) of the EMG signal, during a fatigue protocol.

    METHODS: Four male runners (32±12 yrs) with probes for NIRS over the DLPC and EMG over the VL performed a track running test at a constant speed to fatigue (exhaustion). The running speed was individually determined as the average speed of a 1200-m time trial performed ~3 days prior to testing. For NIRS changes in μmole/L of HbO2 and HbT were computed. The VL EMG-RMS of the contraction of each step was normalized as a percent of a submaximal reference contraction (%RMS), thus removing the non-activity between steps. Data of 10s epochs at 20, 40, 60, 80 and 100% of time for each lap were averaged for analyses. Regression analyses performed with HbO2 and with HbT as dependent variables and %RMS as the independent variable.

    RESULTS: Over time there was an increase in HbO2 and HbT in the DLPC, and in VL-%RMS. Both HbO2 and HbT correlated strongly with EMG-RMS during running to fatigue (see figures below); p<0.001 for both.

    CONCLUSION: The strong relationship between DLPC and VL activities during running to fatigue suggests the involvement of the DLPC in the central processing of fatigue.

  • 146.
    Elfving, Britt
    et al.
    Division of Physiotherapy, Karolinska Institutet, Huddinge, Sweden.
    Åsell, Malin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Bergsten, Charlotte Luning
    Division of Physiotherapy, Karolinska Institutet, Huddinge, Sweden.
    Alexanderson, Kristina
    Karolinska Inst, Div Insurance Med, Dept Clin Neurosci, Stockholm, Sweden.
    Exploring activity limitations and sick leave among patients with spinal pain participating in multidisciplinary rehabilitation2010In: Disability and Rehabilitation, ISSN 0963-8288, E-ISSN 1464-5165, Vol. 32, no 4, p. 292-299Article in journal (Refereed)
    Abstract [en]

    Purpose. To describe limitations in 12 activities at baseline, after multidisciplinary rehabilitation and at a 6-month follow-up for patients with spinal pain and, further, to investigate whether low limitation in any of the activities or in the mean score at baseline might predict increased working time at follow-up. Method. A prospective cohort study of 302 patients, 22- to 63-years old, who participated in multidisciplinary rehabilitation because of chronic neck, thoracic and/or lumbar pain. Data from the Disability Rating Index questionnaire were obtained at baseline, after the 4-week rehabilitation programme, and at the 6-month follow-up. Two subgroups are described: patients who at baseline (1) worked full-time or (2) were on part- or full-time sick leave. Results. The degree of limitation in the 12 activities (items) showed large variations in median scores (7-91). Both subgroups showed significant improvements in most activities after rehabilitation, which remained at the follow-up. Nevertheless, in the sick-leave group, patients who had increased their working time at follow-up (62%) were still very limited in running, heavy work, and lifting heavy objects. In logistic regressions, low limitation in standing bent over a sink at baseline was the only single activity that predicted increased working time at the follow-up: odds ratio (OR) 1.93 (95% CI 1.1-3.5). OR for the mean score was 1.8 (1.0-3.3). Conclusion. A profile of the separate activities demonstrates the large variation in the degree of limitation, which is concealed in a mean score. The single items can be useful when evaluabing interventions. However, to predict increased working time after rehabilitation, the mean score, as well as the activity standing bent over a sink, proved useful.

  • 147.
    Elfving, Britt
    et al.
    Section of Personal Injury Prevention, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden.
    Åsell, Malin
    University of Gävle, Centre for Musculoskeletal Research.
    Ropponen, Annina
    Section of Personal Injury Prevention, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Institute of Biomedicine, Department of Physiology/Ergonomics, University of Kuopio, Kuopio, Finland.
    Alexanderson, Kristina
    Section of Personal Injury Prevention, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    What factors predict full or partial return to work among sickness absentees with spinal pain participating in rehabilitation?2009In: Disability and Rehabilitation, ISSN 0963-8288, E-ISSN 1464-5165, Vol. 31, no 16, p. 1318-1327Article in journal (Refereed)
    Abstract [en]

    Purpose. To identify the factors that predict full or partial return to work among long-term (>= 90 days) sickness absentees due to spinal pain who begin a multidisciplinary rehabilitation programme. Method. In a prospective cohort study, 312 patients with neck, thoracic and/or lumbar pain, aged 20-64, participated in a 4-week multidisciplinary rehabilitation programme in Sweden. Questionnaire data at inclusion were used. Factors included in logistic regressions were as follows: age, gender, type of work, pain location, pain intensity (visual analogue scale), activity limitations [Disability Rating Index (DRI)], health-related quality of life (SF-36), pain-related fear of movement (Tampa Scale of Kinesiophobia), motivation (Self Motivation Inventory), sickness absence at baseline and number of sick-leave days during the previous 2 years. Outcome factor was increased versus not increased working time at follow-up 6 months later. Results. Most patients (68%) reported two or three pain locations. At baseline, 56% were full-time sickness absent and 23% at follow-up; 61% had increased their working time. Predictors for increased working time were age below 40 years, low activity limitation (DRI < 50), low SF-36 bodily pain (>30) and high SF-36 social functioning (>60). Number of sick-leave days during the previous 2 years (md 360; range 90-730) had no influence. Conclusions. Even patients with long previous sick leave can increase working time after a multidisciplinary rehabilitation programme, especially if they are younger, have lower levels of activity limitations and pain and better social functioning. To include information on part-time work is useful when evaluating work ability following rehabilitation programmes.

  • 148.
    Ericsson, Pernilla
    et al.
    Work and Environmental Medicine, Umeå University Hospital, Umeå, Sweden.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Wahlström, Jens
    Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine, Umeå University, Umeå, Sweden.
    Exposure assessment in different occupational groups at a hospital using Quick Exposure Check (QEC): a pilot study2012In: Work: A journal of Prevention, Assesment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 41, no Suppl. 1, p. 5718-5720Article in journal (Refereed)
    Abstract [en]

    In order to test the feasibility and sensitivity of the ergonomic exposure assessment tool Quick Exposure Check (QEC), a pilot-study was conducted. The aim was to test QEC in different occupational groups to compare the exposure in the most common work task with the exposure in the work task perceived as the most strenuous for the neck/shoulder region, and to test intra-observer reliability. One experienced ergonomist observed 23 workers. The mean observation time was 45 minutes, waiting time and time for complementary questions included. The exposure scores varied between the different occupational groups as well as between workers within the occupational groups. Eighteen workers rated their most common work task as also being the most strenuous for the neck/shoulder region. For the remaining five workers, the mean exposure score were higher both for the neck and shoulder/arm in the most common work task. Intra-observer reliability shows agreement in 86% of the exposure interactions in the neck and in 71% in the shoulder/arm. QEC seems to fulfill the expectations of being a quick, sensible and practical exposure assessment tool that covers physical risk factors in the neck, upper extremities and low back.

  • 149.
    Ericsson, Pernilla
    et al.
    Occupational and Environmental Medicine, Umeå University and Hospital, Sweden .
    Lindberg, Per
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Oudin, Anna
    Occupational and Environmental Medicine, Umeå University and Hospital, Sweden .
    Wahlström, Jens
    Occupational and Environmental Medicine, Umeå University and Hospital, Sweden .
    Reliability testing of two ergonomic risk assessment tools2012Conference paper (Other academic)
    Abstract [en]

    INTRODUCTION

    Quick Exposure Check (QEC¹) and Rapid Upper Limb Assessment (RULA²) are two ergonomic risk assessment tools that have been designed to be useful for ergonomists assessing musculoskeletal risk factors in upper extremities at workplaces.

    AIM

    The aim was to describe the variation between and within ergonomists assessments using QEC and RULA, and to compare the two tools regarding within-observer agreement.

    SUBJECTS & METHODS

    Twenty ergonomists observed five different work tasks twice with three weeks in between, watching video clips. They made ergonomic risk assessments using both QEC and RULA.

    The observed work tasks were: Window replacement, nailing a wooden pallet, toilet cleaning, instrumentation in an operating theatre, and sorting post.

    For the statistical analyses, percent agreement and kappa value was used.

    RESULTS

    There was a variation in assessments between the ergonomists in all positions and movements both when using QEC and RULA, except from assessing armposition when observing window replacement using QEC, where all ergonomists assessed the same position (figure 1).

    The ergonomists had higher percent agreement between observation one and two using QEC compared with RULA (table 1).

    CONCLUSION

    There was a variation when assessing positions and movements in different worktasks both between ergonomists and within the same ergonomist using both QEC and RULA. However the agreement between two observations within observers was higher for QEC.

  • 150.
    Eriksson, Per Olof
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Zafar, H
    Temporomandibular disorders2006In: Conn's current therapy 2006 / [ed] Robert E. Rakel, Edward T. Bope, Philadelphia, PA: Saunders , 2006, p. 1197-1202Chapter in book (Other (popular science, discussion, etc.))
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